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SMA America announced the Sunny Boy-US series as the first residential inverter to achieve UL 1741 SA (Supplement A) listing, which represents a significant step in creating a more stable grid and providing the best technology for the residential market.

SMA has completed functional and safety testing with the Sunny Boy-US series of inverters according to the published UL 1741 SA Standard, and Sunny Boy inverters now available for ordering will enable customers to comply with the new standard.

California and Hawaii are the first states to mandate that inverter manufacturers meet the UL 1741 SA requirements of the UL 1741 standard, with compliance required in September 2017. Since it is likely that other states will follow suit, SMA has chosen to upgrade its inverter technology to meet the standard almost a year ahead of schedule.

“Residential solar continues to grow at a rapid pace, and the impact on utilities is significant. Collectively the industry is looking for the best, most effective long-term solutions for a modern grid,” said Sven Schreiber, executive vice president of the Residential business unit at SMA. “SMA recognizes the importance of UL 1741 SA, and has opted to add the necessary functions and features to our inverters immediately. We believe that providing inverters certified to this standard now will save our customers time and money later.”

While the UL 1741 SA listing is not yet mandatory in all 50 states, anyone who wants to comply with the standard can choose SMA inverters knowing they will provide the right features and functions should additional states adopt the same requirements in the future.

Although it is not yet mandatory, SMA believes that complying with the UL 1741 SA requirements as soon as possible is a responsible decision that ensures optimal grid health and stability, while also providing customers with the best possible inverter.

A standard change from the International Association of Plumbing and Mechanical Officials will allow for a sophisticated new design concept that allows PV installers to place panels above existing ABS plumbing vent pipes, instead of designing around them, giving installers the ability to offer more panels, increased power production and improved physical appearance for their customers.

The Solar Roof Jack puts this system in compliance.

Vent pipes are a calculated obstacle in the design of a rooftop array. The most efficient design is still limited by pipes which will unquestionably reduce the percentage of panels sold and installed, as well as the amount of power produced for customers. Selling an extra panel can equal between $1,000 and $1,500 in extra income on the sale of the system.

The updated codes allow for diversion of 1.5 and 2 in. plumbing vents under PV systems using a system such as Solar Roof Jack. (Approved Sept 2016 in IBC and CBC IAPMO IGC 339 2016). The Solar Roof Jack takes into account the angle of the pipe, the angle of the roof and of the solar input available, giving manufacturers and installers more options to offer their customers.

“The current designs are costing homeowners thousands of dollars in potential lost energy production over the life of the system,” says Chris Noel, owner and inventor of the Solar Roof Jack. “There had to be a better way.”

The Solar Roof Jack

Cost and Installation Time

One of the primary beneﬁts is the money saving factor, both for the installer and the solar customer. Since roof vent pipes prevent a customer from utilizing a lot of their roof space, they are being limited to the number of panels they can ﬁt on their roof and therefore losing potential savings that additional panels would have generated. In addition, the installer can now sell more panels because they are no longer limited to working around these vent pipes and are able to save on labor costs because they no longer have to relocate the exposed pipes.

The current installation time of the Solar Roof Jack is approximately eight minutes, keeping crucial installation labor costs to a minimum. Cost is negligible compared to the extra income from additional panels sold and installed.

Many changes are occurring with labeling requirements covered by Article 690 as we move toward the release of the NEC 2017 code revision. PV systems grow and evolve, and the required labeling must change with them to ensure safe and informative installations. Like any evolving process, input from many sources is required to gain a better understanding of what works and what does not, so the process of change can proceed in a way that makes sense for everyday use in real world applications.

Code Making Panel 4 of the NEC 2017 has reviewed hundreds of public inputs. Each suggestion is weighed, reviewed and compared to other similar requests and then voted up or down based on all relevant data and substantiations. Many suggestions were for improved labeling. The panel has addressed a number of inputs; some of the changes are outlined in this article.

New Bipolar PV System Requirements

Making changes that are relevant to existing and future systems is important. Part of the effort has involved addressing labeling efficiency and eliminating or reducing labels that no longer serve a valid purpose. For instance, certain labels are no longer considered necessary, such as the bipolar label listed under 690.7(E)(3) from the NEC 2014 code. Disconnection of the neutral cannot result in overvoltage of the array, since the ground-fault detection system is required to separate the array into two distinct arrays during fault conditions; therefore, condition 3 is unnecessary.

To make this more relevant, the NEC 2017 Article 690.31(I) will now indicate that a new label shall be used to clearly mark bipolar PV systems with a warning notice indicating that disconnecting the grounded conductor(s) (not the neutral) could result in overvoltage of the equipment.

This change is linked to the revisions related to solidly grounded and reference grounded systems. The warning about the disconnection of the grounded conductor in a bipolar system is only relevant for solidly grounded bipolar systems, which are extremely rare. The revision in 690.31(I) for the NEC 2017 clarifies (for reference grounded bipolar systems) that these bipolar arrays must be separated into two distinct monopolar arrays when the grounded conductor is interrupted, so overvoltage does not occur.

Simplifying Power Information

Originally, the NEC 2014 Article 690.35(F) marking requirement was seen as necessary for electricians, based on thinking that ungrounded conductors were somehow unsafe.

Fig. A

That has never been true, and so the requirement for this marking will be eliminated, reducing the number of labels required on a PV system and simplifying the labeling process even more (Fig. A).
Speaking of simplifying labeling, the following labels are still required, but the words “DO NOT TOUCH TERMINALS” have been removed. This is found in 690.17(E) of the NEC 2014 code, but will be found in 690.13 (B) of the NEC 2017 revision (Fig. B).

Fig. B

As of the first draft revision of NEC 2017, 690.53 has changed to simplify the required power information. The examples on pg. 36 show what was preserved in the current code text while also showing what was eliminated or changed (Fig. C).

The following label already exists in Article 690.55 of the NEC 2014, but the language was clarified slightly so that the new NEC 2017 code now reads: “Energy storage systems shall be marked with the maximum operating voltage, including any equalization voltage. If solidly grounded, grounded circuit conductor shall be marked to indicate the polarity.”

Old label

The previous code revision simply indicated: “Photovoltaic power systems employing energy storage shall also be marked with the maximum operating voltage, including any equalization voltage and the polarity of the grounded circuit conductor.”

In the NEC 2014, this section of code required the polarity of the grounded conductor to be marked in all cases. In the 2017 code, only solidly grounded systems need the polarity to be marked as part of this

New Label

provision. Many systems do not have grounded conductors, so the provision in NEC 2014 did not make sense. Also, other marking requirements in 690.31(B) require general markings that include polarity, making this polarity marking requirement redundant.

Note: Solidly grounded means that AC conditions are

Fig. C: In these examples, power requirements were simplified.

used 99 percent of the time.

Click on Page 2 for changes for stand-alone systems and updated Rapid System Shutdown labels

Trina Solar Limited announced the North America launch of Trinaswitch, its next generation of smart solar modules. This module builds new technology into the junction box, allowing a more seamless integration for safety and compliance.

“Trinaswitch is a continuation of Trina Solar’s product strategy in adding smart functionality to solar photovoltaic modules to reduce the balance of system cost, boost system safety and ultimately reduce costs to end users,” said Jing Tian, Trina Solar’s head of global marketing.

The Trinaswitch smart module includes upgradeable functionality such as string flexibility and advanced optimization performance features. Trinaswitch modules are NEC 2014 690.12 compliant and meet the 2014 NEC Rapid Shutdown safety standard, which is now required in more than 24 states. By 2017, nearly all U.S. states will be required to meet this standard.

Trinaswitch smart modules are constantly monitoring PV module parameters such as overvoltage, overtemperature and overcurrent. The smart module will enter PV-Safe mode if a safety hazard is detected and reported to the Cloud Connect. The Cloud Connect will decide whether there is a local threat that can be avoided by shutting down a single module, or if there is a potential system safety hazard and PV-Safe mode is needed for the entire system.